Process of producing feed products



July 4, 1961 B. CLAYTON PROCESS OF PRODUCING FEED PRODUCTS Filed Aug. 8.1957 Sourog Material [0 3/ 4/ i solvent. Extractor Meal 3 OH 47 CausticI 5/ 53' fiada fish X6 h54 Color Bodies 5'6 Desolvent'izer q 63' g 0rDryer Hzot 65 peHetizer 5 Refined Oil Fed Pellets Feed /A/ vs/v To aEENdHM/N CLHVTON BY H/S QTTORNL'YS IL/RRRIS, Mac/4, 557-5? HARRIStherein are intact in the sense of being substantially 4 Claims. (Cl.99-2) My invention relates to a process for producing feed products,particularly animal feed products, from beans, seeds or otheroil-bearing vegetable material.

Such source material is. conventionally processed by pressing, solventaction or both to extract crude glyceride oil therefrom, leaving aresidual meal which is widely used as an animal feed or an additivethereto. Particularly if the oil is extracted by solvent extraction, themeal contains very little residual oil and it is desirable that its fatcontent be increased by adding thereto oils or fats from other cheapsources thereof. Much of the oil is commercially refined by mixingaqueous caustic soda therewith in suflicient stoichiometric excess toreact with the free fatty acids of the oil and produce soaps whichappear as a part of the soapstick separated from the oil bygravitational or centrifugal action.

It has been proposed to return such separated caustic soapstock to theextracted meal to supply the fat deficiency thereof. However, theresulting feeds leave much to be desired as concerns nutritive andgrowth factors. One reason for this is that the caustic alkali reactswith or degrades the gums of the oil, which appear in the soapstock asconstituents of little or no value because the otherwise valuable gumshave been degraded or destroyed by the caustic alkali, making themrelatively ineffectual in promoting the desired growth of the animal.Such caustic-degraded gums are not soluble in petroleum ether.

It has also been proposed to employ soda ash as the alkali, the gums inthe separated soapstock being the-n not substantially alkali-degraded.Nevertheless, it is known that soda ash refining does not usually reducethe color or other impurities of the oil to a sufficient extent,requiring a subsequent refining with caustic to produce a high qualitymarketable oil. This, together with the large excesses of soda ash andthe new equipment costs involved, makes this process not commerciallyattractive to many refiners.

It has now been found that refining by the joint use of caustic and sodaash can produce unexpected benefits if the caustic is employed incarefully limited amount. If the two alkalis are employed sequentially,the resulting soapstock makes an excellent feed additive. The gtfims reeof alkali degradation.

It is an object of the invention to provide a novel process of producingfe'eds by refining a crude glyceride oil by the joint use of caustic andsoda ash, separating the resulting soapstock and adding same to a feedproduct, typically to the meal remaining after the oil has beenextracted from the source material by any conventional method.

A further object lies in the refining of the oil by careful controlof'the amount of caustic employed. In this respect, it is an object ofthe invention to limit the caustic to an amount about 50-85% of thatwhich would be necessary to neutralize all of the free fatty acids. Itis a further object of the invention to add soda ash to the oil-causticmixture while containing residual fatty acids.

A further object of the invention is to provide a process for refiningthe'crude oil to produce a soapstock which 'containsboth caustic andsoda ash soaps along with the gums of the oil in substantiallyundecomposed state. A further object is to produce a soapstock of thistype the gums of which are substantially completely soluble in petroleumether. Another object is to control the steps of the process to producea soapstock which separates cleanly from the oil, the entire processminimizing refining losses and being well balanced in the economic valueand usefulness of the various products produced.

Further objects and advantages of the invention will be evident to thoseskilled in the art from the herein exemplified embodiments of theinvention.

The drawing is a pipe-line diagram of one type of apparatus capable ofcarrying out the processes of the invention.

The source material, typically seeds or beans suitably ground or flakedand sometimes precooked, are delivered to an extractor 10. Here oil isextracted from the source material by pressing, solvent action or both,the oil being delivered through a pipe 11 to a tank 12 for temporarystorage, the extractor producing a meal advancing along a path or line13. A pipe 14 may supply an oil solvent to the extractor 10, thissolvent being either removed ahead of the tank 12 or remaining wholly orpartially associated with the oil throughout the subsequent steps in theprocess if it is desired to practice the process in the miscella stage.In the latter event, the tank 12 will be made pressure tight or may beeliminated.

The crude oil may be withdrawn from the tank 12 by a pump 15, beingheated if desired in a heat exchanger 16 and being delivered as acontinuous stream to a flow mixer 17. The pump 15 is a part of aproportioning system,

diagrammatically shown as driven by a motor 18 which,

through speed changers 19 and 20, drives pumps 21 and 22 at speedsproportional to the pump 15.

The pump 21 withdraws an aqueous caustic solution from a tank 24 anddelivers a stream thereof through a heat exchanger 25 and a valve 26 tothe fiow mixer 17 where the caustic and the oil are initially mixed, Theflow mixer may be merely a pipe junction if desired. The mixture is sentimmediately to a pipe-line mixer 30* in cluding a suitable rotaryagitator driven by a motor 31 to eifect a very thorough-and uniformmixing of the oil and caustic in a very short period of time. Due to thefact that the amount of caustic proportioned by the pump 21 isinsuflicient to neutralize the free fatty acids of the oil, the mixturedischarged from the mixer 30 will contain caustic soaps, residual fattyacids and gums substantially free of caustic degradation. The time inthe mixer 30 is a matter of seconds and it is often desirable to allowfor a brief hold-up period beyond the mixer to condition the mixturebefore the soda ash solution is added. For this purpose, the mixture mayEflOW through a larger pipe section 3 3, typically a five-inch pipeseveral feet in length, before reaching a flow mixer 35. I

A suitable soda ash solution is withdrawn from a tank 37 by the pump 22and may be adjusted in temperature by passage through a heat exchanger38 before being delivered to the flow mixer 35. Again, the resultingmixture is immediately delivered to a pipe-line mixer 40 driven by amotor 4-1 to mix the soda ash solution therewith thoroughly and in ashort interval of time. The stream of the resulting mixture may beadjusted in temperature by flow through a heat exchange device 42 beforebeing delivered to the separation equipment. Alt this stage of theprocess, the oil stream contains caustic soaps, soda ash soaps, and gumsfree of alkali degradation, plus water which has been added as a part ofthe caustic and soda ash solutions. In addition, the stream may containthe excess soda ash and part or all of the oil solvent if the refiningis to take place in the miscella. The soapstock separable from thestream will include the aforesaid soaps and gums, together with aminimum amount of entrained oil.

While the soapstock separation can be efiected batchwise and bygravitational methods, I prefer to employ continuous centrifugalseparation effected in a-centrifuge 45 which may be of the closed orhermetic type, particularly if some of the oil solvent is present in theentering stream. Water or aqueous solutions of separation-promotingagents, typically salt solutions, can be proportioned into thecentrifuge 45 through the pipe '46 to facilitate the separation of thesoapstock from the oil. but are usually not needed. The oil andsoapstock respectively discharge through spouts 47 and 48 of thecentrifuge.

The separated oil may or may not be in a marketable condition at thetime of discharge from the centrifuge 45. Usually it is desirable torerefine this oil to remove additional color bodies and otherimpurities. This can be done in accordance with the process of ClaytonRe. 23,680, using a concentrated caustic solution. Thus, the oil may beadjusted in temperature by passage through a heat exchanger 49 and maybe mixed with a concentrated caustic solution in mixers 50 and 51 beforebeing delivered to a centrifuge 52. Water or aqueous diluent is added tothe entering mixture or to the interior of the centrifuge through a line53. In this way the centrifuge 52 discharges an aqueous materialcontaining the color bodies through a spout 54 and a purified. oilthrough a spout 55, the purified oil being washed and dried in suitablewashing equipment 56 and drying equipment 57 to produce the desiredrefined oil. If, as is desirable, the caustic solution in the tank 24 isrelatively concentrated, this same caustic solution can be used in thererefining steps, being proportioned either by the pump 21, as shown, orby a separate pump. The drawing shows a portion of the caustic solutionfrom the pump 21 flowing through a valve 58 to the mixer 50.

The meal in the line 13 is. delivered to a mixer 60 which also receivesall or a pontion of the soapstock from the spout 48 through a line 61.The resulting mixture advances to a desolventizer or dryer 63 whereinheat is applied to remove Water vapors and vapors of residual solvent,indicated by the arrow 64. -In some instances, the mixer 60 and thedesolventizer or dryer 63 can be unified. The presence of solventfacilitates the uniform mixing of the soapstock in the meal. Inaddition, the heat in the desolventizer can be employed to detoxifygossypol present in most cottonseed meals or soapstocks. Necessarydetoxifying temperatures are =less when applied to the mixture thandetoxifying temperatures applied separately to the meal and thesoapstock. The resulting soapstockfortified meal may be dischargedthrough a line 65 as the feed product or it may be sent to pelletizingequipment 66 for formation of feed pellets discharging at 67.

Usually all the separated soapstock can be advantageously returned tothe meal but lesser amounts can be employed if desired. Amounts from afraction of a percent up to percent are usually employed. Thetemperature in the dryer 63 is usually in the range of 180 to 250 F.,the higher temperatures in this range effecting substantialdetoxification of gossypol-containing soapstocks or meals or both.

One of the most important features of the present invention is thelimitation in amount of caustic soda mixed with the crude oil. In normalprocesses in which sufficient caustic soda is employed to react with allof the free fatty acids, the excesses over stoichiometric amounts resultin an attack on the gums or phosphatides, changing them from abeneficial petroleum-ether-soluble form into a degraded form ofsubstantially less value not substantially soluble in petroleum ether.On the other hand, it is a feature of the invention that the amount ofcaustic should be less than that required to neutralize the free fattyacids, the alkali being then largely selective in its action and beingquickly expended in neutralizing a corresponding amount of the freefatty acids, with little or no decomposition of the gums and little orno reaction with the oil, particularly if the mixing is rapid anduniform. Non-uniform mixing tends to form local pockets of strongcaustic that can saponify neutral oil or attack the gums. However, byuse of the flow mixer 17 and the pipe line mixer 30, the relativelystrong but limited amount of caustic is mixed very thoroughly andrapidly with the oil. It is desirable that the mixing at this stage hecompleted in as short a time as possible. Best results have beenobtained by mixing with the oil an amount of caustic equal to about5085% of that amount that would be necessary to neutralize the freefatty acids of the oil. The remaining or residual fatty acids are thenneutralized by the later-added soda ash solution, with many attendantadvantages.

The caustic soda is preferably added in aqueous solution. Best resultshave been obtained by employing a relatively concentrated solution butsolutions ranging from 12 B. to as high as 50 B. can be employed. Thelower concentrations are best for oils low in free fatty acids, e.g.,less than 1%, while the higher concentrations are best for the higherfree fatty acid oils, e.g., 5% or greater. The preferred range ofconcentrations is about 20-36 B.

The soda ash is likewise preferably added in the form of an aqueoussolution. Solutions ranging from about 10 B. to saturation can beemployed, the range of about 1022 B. being preferred with 20 B. solutionbeing satisfactory in most instances.

Sufficient soda ash solution should be added to complete the reaction ofthe free fatty acids. In addition, if the caustic deficiency has beensuch as to produce acid soaps, the amount of soda ash should besufiicient to react therewith. Such acid soaps are much more soluble inthe oil than normal soap but are converted into the latter by the sodaash employed. The actual amount of soda ash employed will be in excessof that stoichiometrically equivalent to the residual fatty acids.Preferably the excess should be sufficient to prevent the evolution ofcarbon dioxide in or ahead of the centrifuge 45.

It is diflicult to set forth precisely the exact amount of soda ashsolution that will be best in all processes, particularly as there arefactors other than residual free fatty acids, suppression of carbondioxide, etc. that enter the picture. I have found that best resultsfollow from the use of an amount of soda ash calculated on the followingbasis:

Percent dry soda ash=0.0750.15 Wesson Loss of crude oil.

This formula gives good results if, as is contemplated, the amount ofcaustic soda is in the range of about 50-85% of that required toneutralize the free fatty acids, irrespective of the exact amountemployed within that range. The Wesson Loss is a well known property ofglyceride oils, being expressed in a percentage figure and beingdetermined by the method described on pages 400-402 of Vegetable Fatsand Oils by G. S. Iamieson, published in 1932 by The Chemical CatalogCompany, New York, N.Y. If this numerical figure is multiplied by 0.1,the result will be the desirable amount of dry soda ash to be employedon most oils. For oils high in gum content and low in free fatty acidcontent, the multiplication factor may be between 0.1 and 0.15, often ator near the upper value of this range. For oils of very high Wesson Lossthe multiplication factor may be as low as 0.075.

An example in which the formula is applied is as follows:

A crude soya oil containing 0.5% free fatty acids and 1.5% gums andhaving a Wesson Loss of 2.0% can be refined in accordance with theinvention by adding 0.15% of a 30 B. (24%) solution of caustic soda,representing 50% of the amount required to neutralize the free fattyacids. The amount of soda ash to add, using a multiplication factor of.1 in the above equation, is 20% dry soda ash. This corresponds to 1.33%of a 20 B. soda ash solution. The soapstock from this refining willcontain about 30.8% moisture and 20.0% free oil, dry basis.

In another example, a crude cottonseed oil containing 5.0% free fattyacids and 1.5% gums with a Wesson Loss of 6.5%, is refined by adding2.5% of 30 B. caustic soda solution, representing 85% of the amountrequired to neutralize the free fatty acids. Using the multiplicationfactor of 0.1 in the above equation, the dry soda ash equals .65 If a 20B. solution is to be employed, 4.3% thereof would be the calculatedamount. The soapstock from this process Will contain about 35% moistureand about 20% free oil, dry basis. i

The addition of soda ash to the mixture-of oil, caustic soaps, residualfree fatty acids and gums or phosphatidic materials results in a numberof advantages. The soda ash not only completes the reaction with thefree fatty acids but makes the gums and soapstock more insoluble in theoil, thereby making it possible to effect a more complete, efficient andeffective refining ofthe oil. If any acid soaps have formed, these areneutralized and made insoluble in the oil. If any localizedconcentration of the caustic exists, resulting from imperfect mixing,this is quickly dissipated and the localized causticity reduced by thesoda ash solution, which also acts as a buffer to prevent anysubstantial attack by the caustic on the gums or phosphatides so thatthe latter remain intact and in a form soluble in petroleum ether.Addition of the soda ash solution also assists in breaking the emulsionso that the separated soapstock has a minimum content of 00- cluded oil,thus increasing the oil yield from the complete process and the economicvalue thereof. Further, the addition of the soda ash solution after thecaustic gives a soapstock which is readily separable and pumpable,having a desirable moisture content, eg. about 2545% usually about30-35%. Finally, the soda ash soaps and the carbonated gums, present inthe soapstock along with the caustic soaps, appear to augment to anunexpected degree the growth and nutritive value of meals or feeds towhich they are added.

The temperature in the various portions of the process is notparticularly critical. Best centrifugal separation in the centrifuge 45is obtained if the entering mixture is about 190-200 'F., althoughtemperatures of l60-2l0 F. can be employed. The oil from the extractoris usually cooled to about 80100 F. the additional heat can be suppliedpartly or entirely by the heat exchanger 42 just ahead of the centrifuge45. Sometimes, however, a portion of the heat may be supplied in theheat exchanger 16. In addition, the caustic solutionand the soda ashsolution can be heated in their respective heat exchangers 25 and 38.

The oil issuing from the spout 47 of the centrifuge 45 will usuallycontain less than 0.10% free fatty acids while the soapstock issuingfrom the spout 48 will contain about to 22% free oil, usually aboutthereof, dry basis. If the oil is to be rerefined, this may be done bymixing therewith a relatively strong caustic solution of about 20-50" B.before or while the oil is at a temperature of about 80-100 F.,preferably, and the mixture subsequently heated to l20180 F. beforecentrifuging. To permit separation into the two phases previouslymentioned, the resulting mixture is diluted by water or other aqueousdiluting agent added through pipe 53 to the mixture or to the interiorof the centrifuge. The amount of the diluting agent will desirably besuch as to reduce the concentration of the excess caustic solution to 10B. or less. The amount of strong caustic solution added through themixer 50 will be substantially in excess of the amount required to reactwith any residual impurities in the oil and will usually be 0.5-3.0% ofthe caustic solution.

The following examples will illustrate typical applications of theprocess in practical operation.

Example I As an example of a process employing caustic soda solution inamount about 70% of that required to neutralize the free fatty acids, acrude cottonseed oil having 2.7% free fatty acids, a Cup Loss (by theOfiicial Method, American Oil Chemists Society) of 9.7% and a Wessono'r' Absolute loss of 4.5% was refinedwith 1.12% of 30 B. caustic sodasolution proportioned in flow into the crude oil at a temperature of F.The solution was very rapidly and intimately mixed, using a pipe-linemixer 30 with its agitator rotating at a speed of 3600 r.p.m. After aresidence time in flow of 20-30 seconds in the larger pipe section 33,2.6% of 22 B. soda ash solution (17.5% Na CO was proportioned into themixture, the resulting mixture being quickly mixed in a similarpipe-line mixer and then heated to -200 F. in the heat exchanger 42. Theresulting centrifuged oil was rerefined with 1.25% of 30 B. causticsoda, waterwashed and vacuum-dried. The refining loss was 5.63%, whichloss was 42.0% lower than the ofiicial Cup Loss. The entire soapstock,separated in the centrifuge 45, is desirably returned to the meal aheadof the desolventizer or drier 63. The amount of soapstock in the mealwas about 2.75% by weight.

Example 11 Evidencing an operation in which the amount of caustic was80% of the amount that would be required to neutralize the free fattyacids, a crude cottonseed oil containing 8.4% free fatty acids, Cup Loss24.3%, Wesson Loss 10.84%, was refined with 4.0% of 30 B. caustic sodaand 5.6% of 24 B. soda ash solution (19.2% Na CO was mixed in the samemanner and under the same conditions as Example I. The separated oil wasrerefined with 1.5% of 30 B. caustic. The refining loss was 14.68% or39.6% lower than the Cup Loss. This represents a saving of 5,772 lbs.for a tank car of 60,000 lbs. of crude oil. The soapstock was anexcellent feed additive.

Various changes and modifications can be made without departing from thespirit of the invention as defined in the appended claims.

I claim as my invention:

1. A process for producing animal feed products from source materialssuch as vegetable seeds and beans, which process includes the steps of:processing said source material to extract therefrom a crude glycerideoil and produce a residual meal, said oil containing gums and free fattyacids; mixing with the crude oil an amount of caustic sufficient toneutralize only about 50-85% of the fatty acids of the oil therebyproducing a mixture of oil containing soaps, residual fatty acids andgums; mixing with said mixture before separation of the constituentsthereof an amount of soda ash in excess of that required to neutralizesaid residual fatty acids to produce a resulting mixture, said soda ashbeing added in aqueous solution, the amount of the soda ash beingapproximately the amount determined by the equation:

Soda ash=0.075-0.15 Wesson Loss of the oil where the amount of soda ashis expressed as percent of dry soda ash; separating from the resultingmixture a soapstock containing caustic soaps, soda ash soaps and gumsfree of substantial alkali degradation and substantially completelysoluble in petroleum ether and mixing at least a part of said separatedsoapstock with said meal.

2. A process for producing an animal feed product, comprising: mixingwith a crude glyceride oil containing free fatty acids and gums and ofknown Wesson Loss an amount of caustic soda solution sufficient toneutralize only about 50-85% of such free fatty acids to form causticsoaps therein; then mixing with the oil while said caustic soaps andgums are present an amount of soda ash determined by the equationi Sodaash=0.075-0.15 Wesson Loss where the amount of soda ash is expressed aspercent of dry soda ash; separating the resulting mixture into oil andsoapstock containing caustic soaps, soda ash soaps, gums substantiallyfree of alkali degradation and substantially completely soluble inpetroleum ether, and water; and

adding to a feed product an amount of said soapstock ranging from afraction of one percent to about .five

percent. v V p 3. A process for producing from a crude glyceride .oilcontaining gums and free fatty acids a soapstock having excellent growthand nutritive factors when added to a feed product, said oil having aknown Wesson Loss, which process includes the steps of: mixing with thecrude glyceride oil an amount of aqueous caustic soda solutionsufficient to neutralize only about 508'5% of such free fatty acids toform caustic soaps in the oil; then mixing with the oil while saidcaustic soaps and gums are present an amount of soda ash determined bythe equation:

Soda ash=0.075-0.15 Wesson Loss where the amount of soda ash isexpressed as percent of dry soda ash, said soda ash being mixed with theoil in aqueous solution; and separating the resulting mixture into oiland soapstock containing caustic soaps, soda ash soaps, gumssubstantially free of caustic degradation and substantially completelysoluble in petroleum ether, and water.

4. A process as defined in claim 3 in which said aqueous caustic sodasolution is of a concentration about 12-50 363., in which the aqueoussoda ash solution is of a strength ranging from about 10 B. tosaturation, and in which sufficient water is present during theseparation of the soapstock to produce a soapstock containing about25-45% water.

OTHER REFERENCES Ault et al.: Chemurgic Digest, December 1944, pp. 4, 5,and 19.

Bailey: Ind. Oil and Fat Products, Ind. Ed. (1951),

20 Interscience Pub., N.Y.C., pp. 643-9.

1. A PROCESS FOR PRODUCING ANIMAL FEED PRODUCTS FROM SOURCE MATERIALSSUCH AS VEGETABLE SEEDS AND BEANS, WHICH PROCESS INCLUDES THE STEPS OF:PROCESSING SAID SOURCE MATERIAL TO EXTRACT THEREFROM A CRUDE GLYCERIDEOIL AND PRODUCE A RESIDUAL MEAL, SAID OIL CONTAINING GUMS AND FREE FATTYACIDS; MIXING WITH THE CRUDE OIL AN AMOUNT OF CAUSTIC SUFFICIENT TONEUTRALIZE ONLY ABOUT 50-85% OF THE FATTY ACIDS OF THE OIL THEREBYPRODUCING A MIXTURE OF OIL CONTAINING SOAPS, RESIDUAL FATTY ACIDS ANDGUMS, MIXING WITH SAID MIXTURE BEFORE SEPARATION OF THE CONSTITUENTSTHEREOF AN AMOUNT OF SODA ASH IN EXCESS OF THAT REQUIRED TO NEUTRALIZESAID RESIDUAL FATTY ACIDS TO PRODUCE A RESULTING MIXTURE, SAID SODA ASHBEING ADDED IN AQUEOUS SOLUTIOIN, THE AMOUNT OF THE SODA ASH BEINGAPPROXIMATELY THE AMOUNT DETERMINED BY THE EQUATION: